Sony vFET pt2 N channel help

[Zen Mod]

in a meantime, read this, hoping it'll give you some insight in possible culprit

(check both zener diodes, too)

Thread 'Lottery DIY Sony VFET pt 2 (N-Channel) - assembly by Mighty ZM'

2022-05-06 12:48 pm

Coverage of assemblage of Lottery amp for my dear Friend, way of paying back for valuable help he gave in some of my endeavors

He's extraordinary busy in last several months, so ......

Amp No. 122, member tunasto here, Vinko at Baby DiyA

Let's start with schematics - I like when schematics are present

• Zen Mod
• Replies: 69
• Forum: Pass Labs

 

[Antealta]

Will do

 

[Antealta]

Hi

Z1 Zener diode is shorted

Andreas

 

[Antealta]

Is it possible to use 20V Zener or should I order 18V

And what could be the reason for this to happen in the first place, power spikes from supply

Andreas

 

[Zen Mod]

Gremlins?

you can use 20V zener, protection part, so perfectly in needed range

 

[Antealta]

Ok

Yeah probably gremlins 😀

 

[Antealta]

Hi

I change the two zener and the opto, still no power draw.

Did som noob measurement, between case (IRF250)and + on the good side it’s a short, on the bad side it’s 60Kohm

Between case/nut (Vfet) and marked S on schematic, short on good side, on bad side ≈40Kohm

Andreas

 

[Zen Mod]

remove screws, inspect, clean if needed, put screws back, check with DMM

inform here, pics if possible

 

[Antealta]

Will do

 

[Antealta]

Hi

I measured between S and D on bad one, there is nothing, on the good one it’s a short
And measure between D and G and both shows the same, se picture. Bad one to the left.

It’s toast right?

Andreas

 

[Zen Mod]

bummer

 

[Antealta]

Yes a bummer..

And now for something completely different.

Do you still have/make sell babelfish x252set?

Andreas

 

[Zen Mod]

yes, but slightly paused, implementing local protection to driver buffer

hope to get them (pcbs) checked in vivo in few weeks

 

[Antealta]

Ok
Thanks